Text mask bug got grandfathered in R7

Let’s fix it once and for all, please!

It even prints crappy:

we always try to fix stuff like this… can you give us a file with steps to repeat? I’ll get it written up and in front of the appropriate dev-

can you also post the results of running the systeminfo command on your copy of rhino?

We don’t need a sample and the bug is still on my list. This is a zbuffer issue that happens in perspective viewports